Method for preventing the degradation of a hydrophilic colloid solution for silver halide photographic light-sensitive material

ABSTRACT

A method for preventing the degradation of a hydrophilic colloid solution for a silver halide photographic light-sensitive material of which the viscosity has been or is to be increased using an anionic polymer containing an acid group, which comprises incorporating into the hydrophilic colloid solution at least one compound represented by the formula (I): ##STR1## wherein R.sub. represents a hydrogen atom or an alkyl group; and R 2 , R 3  and R 4 , which may be the same or different, each represents a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the preparation of silver halidephotographic light-sensitive materials, and more particularly, to anovel method for preventing the degradation of a hydrophilic colloidwhich is employed as a binder for silver halide photographic materials.

2. Description of the Prior Art

In general, silver halide photographic light-sensitive materialscomprise a support having thereon one or more light-sensitive silverhalide emulsion layers and, depending upon necessity, having furtherthereon layers such as a subbing layer, an intermediate layer, a filterlayer, an antihalation layer, a protective layer, etc. Known hydrophiliccolloids which are employed as binders for these photographic layersinclude proteins such as gelatin, albumin, casein, etc.; cellulosederivatives such as carboxymethyl cellulose, hydroxyethyl cellulose,etc.; saccharide derivatives such as agar, sodium alginate, starchderivatives, etc.; synthetic hydrophilic colloids such as polyvinylalcohol, poly-N-vinylpyrrolidone, polyacrylic copolymers, etc. Of these,gelatin is most generally employed. Further, the gelatin can be replacedpartially or completely by gelatin derivatives, i.e., those obtained bytreating the amino groups, imino groups, hydroxy groups or carboxylgroups which are present as functional groups in the gelatin, withcompounds capable of reacting with these groups, or by graft polymersobtained by grafting the molecular chains of high molecular weightsubstances, and the like, onto the gelatin molecule. Alternatively, useof two or more kinds of hydrophilic colloids, e.g., the use of a mixtureof gelatin and other high molecular weight substances, in combination isalso known.

On the other hand, it is known that these hydrophilic colloids employedfor silver halide photographic materials deteriorate, decay or aredecomposed by the action of bacteria, molds, yeasts, etc. For example,upon preparation of photographic materials, if these hydrophiliccolloids deteriorate or are decomposed, the viscosity of the coatingsolution and the physical strength of the coated layer are reduced, and,in addition thereto, localized decomposition of these hydrophiliccolloids occurs so that uniformity of the coated layers is lost, or thedecomposition products of hydrophilic colloids adversely affect thephotographic properties in certain instances.

In order to prevent this deterioration or decomposition (hereinafter theterm "degradation" will be used to describe collectively all of thesedeleterious changes which occur) of hydrophilic colloids employed forphotographic materials due to bacteria, molds, yeasts, etc.,preservatives or antifungal agents have been incorporated into solutionscontaining the hydrophilic colloids described above at some stage duringthe preparation of the photographic materials.

Agents which can be used, in general, as preservatives or antifungalmaterials include, for example, aromatic hydroxy compounds such asphenol, thymol, trichlorophenol, tetrachlorophenol, pentachlorophenol,cresol, p-chloro-m-cresol, o-phenylphenol, benzylphenol,2-benzyl-4-chlorophenol, chlorophen, dichlorophen, bromochlorophen,2,2'-dihydroxy-5,5'-dichlorodiphenyl monosulfide,2,4,4'-trichloro-2'-hydroxydiphenyl ether, 3,4,5-tribromosalicylanilide, or the salts thereof; compounds containing a carbonyl groupsuch as formaldehyde, paraformaldehyde, chloroacetaldehyde,glutaraldehyde, chloroacetamide, methylol chloroacetamide; carboxylicacids or esters thereof such as benzoic acid, monobromoacetic acidesters, p-hydroxybenzoic acid esters, sorbic acid; amines such ashexamethylenetetramine, alkylguanidines,nitromethylbenzylethylenediamine; disulfides such as tetramethylthiuramdisulfide; nitrogen-containing heterocyclic compounds such as2-mercaptobenzothiazole, 2-(4-thiazolyl)benzimidazole,2-methoxycarbonylaminobenzimidazole; organic mercury compounds such asmercury phenylacetate, mercury phenylpropionate, mercury phenyloleate;antibiotics such as neomycin, kanamycin, polymycin, streptomycin,furamycin, and the like. Some of these compounds are also known to besuitable for use in photography. However, the effects of these agentsare exhibited only when a large amount of these agents is added tohydrophilic colloids and, in most cases, these agents are hazardous tohumans, effective only against certain bacteria, are harmfulphotographically, or mutually interact with other photographicadditives. For example, phenols such as phenol and thymol which are veryoften employed do not provide sufficient preservation effects unlessthey are present in the hydrophilic colloids in an amount of about 2 wt%or more. In addition, phenols provide less preservation and antifungaleffects against molds or yeasts and are strongly toxic to humans, eventhough they are effective against bacteria. Further, aldehydes such asformaldehyde are effective against bacteria but only slightly effectiveagainst molds and are harmful to humans and further fog in silver halidephotographic light-sensitive materials tends to occur when they areused. Further, heterocyclic compounds such as benzothiazole result indeleterious photographic effects such as desensitization in certaininstances. Organic mercury compounds are only slightly effective againstbacteria and are harmful to humans, although they are effective againstmolds. Antibiotics such as neomycin, kanamycin are ineffective againstyeasts, although they are effective against bacteria.

As described above, many preservatives are known. However, theseconventional preservatives are not directly usable as preservatives forphotography. This is because, as is well recognized in the art,extremely delicate handling is necessary in photographic area. Allphotographic additives must have the following photographic properties:(1) they must not cause a reduction in sensitivity to occur, especiallyduring storage under high temperature and high humidity, (2) they mustnot cause a change in gamma to occur, (3) they must not cause fog, (4)they must not adversely affect the stability of latent images formed,and (5) the processing must be smooth when they are used. For example,it is known that conventional phenol type preservatives causedesensitization under the conditions of high temperature and highhumidity when the amount employed is high in order to obtain sufficientpreserving activity. Neomycin also causes desensitization at highhumidity and high temperature. Therefore, it has been long desired todevelop all-round preservatives which do not adversely affectphotographic properties.

On the other hand, uniformity of the layers of photographiclight-sensitive materials and coating at a high speed are desired. As aresult, it is necessary to control the viscosities of respective layersto desired values in order to enable uniform coating at high speed,particularly where two or more layers are coated simultaneously orcontinuously using coating techniques such as extrusion coating, curtaincoating, air knife coating, or the like. In particular, where thecoating is onto a support travelling at a speed of about 20 m/min ormore, it is difficult to achieve uniform coating if the viscosity of thecoating solution is low. In addition, where two or more layers aresimultaneously coated, the relative values of the viscosities of thecoating solutions for the respective layers must be adjusted so thatuniform coating can be achieved.

Viscosity-increasing agents must be added to photographic coatingsolutions to facilitate uniform coating of the coating solution onto asupport. Particularly in the past several years, the demand for highspeed coating has been increasing and high speed coating on anindustrial scale is achieved by increasing the viscosity of a coatingsolution.

Another demand is to improve the quality of a photographic element byconverting photographic layers into a multilayered structure, generallycomposed of 6 to 20 layers. In such a case, it is essential for theviscosities of the coating solutions to be well balanced among thelayers by purposely using viscosity-increasing agent. In addition,enhancement of viscosity using viscosity-increasing agents saves gelatinwhich is expensive since gelatin is often employed also as aviscosity-controlling agent due to the photographically inert propertiesof gelatin.

It is known to incorporate polymers containing acid groups such ascarboxyl groups or sulfonyl groups into coating solutions to increasethe viscosity of coating solutions for photographic layers.

For example, a method for increasing the viscosity by incorporating acompound of the general formulas: ##STR2## wherein R₀ represents analiphatic or aromatic hydrocarbon residue and S represents a sulfonicacid group, a salt thereof or a derivative thereof, --SO₃ R'₁, --SO₃ X,or --SO₂ NR'₁ R'₂, wherein R'₁ and R'₂, each represents a hydrogen atom,an alkyl group, an aryl group or an aralkyl group; and X represents anammonium group, a potassium atom, a sodium atom or another alkali metalatom; into a solution containing gelatin is described in Japanese PatentPublication No. 3582/1960.

Further, Photographic Science and Engineering, Vol. 14, pages 178 to 183(1970) discloses that ammonium salts of copolymers of maleic anhydrideand methyl vinyl ether, polystyrene sodium sulfonate, polyvinyl ammoniumphthalate, dextran sodium sulfate, etc., can be employed asviscosity-increasing agents for gelatin and derivatives thereof. Inaddition, Japanese patent application (OPI) No. 45830/1972 (The term"OPI" as used herein refers to a "published unexamined Japanese patentapplication") discloses that polymers or copolymers of acrylic acid,maleic acid or styrene sulfonic acid, or cellulose derivativescontaining acid groups (e.g., carboxymethyl cellulose, cellulosesulfate) can be incorporated into a gelatin intermediate layer.

As stated above, phenol preservatives such as phenol or thymol which aregenerally employed as preservatives for hydrophilic colloids forphotography have the disadvantage that the preservation effect is notobtained unless a large amount thereof is added to hydrophilic colloids,due to their poor preservation effect. For instance, in the case of aphotographic coating solution using gelatin as a hydrophilic colloid, asufficient preservation effect is not obtained unless the phenols areemployed in an amount of 2 wt% or more based on the gelatin (solidscontent). As such, where a large amount of phenol is incorporated inphotographic coating solutions, there is the disadvantage that it isdifficult to produce a uniformly coated layer since gelatin tends toaggregate in the coating solution. Where anionic polymers for increasingthe viscosity are incorporated into photographic coating solutionscontaining a phenol, a large amount of a viscosity-increasing agent mustbe added because the viscosity-increasing effect is prevented by thephenol.

A photographic hydrophilic colloid solution, e.g., an aqueous gelatinsolution, necessarily has a cationic pH. In order to prevent degradationof such a photographic solution, preserving activity can be mosteffectively achieved by causing an ionic interaction of the resultingcationic phase with an anionic compound. In addition, bacteriathemselves do not grow in a low pH range so that the use of an acidiccompound is dictated as a preserving agent.

Conventional preservatives severely restricted as to functionalrequirements are extremely pH-dependent. For example, benzoic acid,sorbic acid and benzyl alcohol, which are most typical preservatives fora gelatin solution, exhibit their preserving activity only up to aneutral pH at the highest.

The most serious problem is, as stated above, the undesired reduction inviscosity of the system when such conventional preservatives and anionicpolymer viscosity-increasing agents are used in combination.

As a result, it has been desired to develop preservatives forphotographic hydrophilic colloids which exhibit a variety ofpreservation effects and which can be used in a small amount, i.e.,which exhibit marked anti-degradation and antifungal effects againstbacteria, yeasts, molds, etc. In addition, it has been desired todevelop preservatives for photographic hydrophilic colloids which do notadversely affect the viscosity-increasing effects ofviscosity-increasing agents.

SUMMARY OF THE INVENTION

Thus, an object of the present invention is to provide a method forpreserving solutions of hydrophilic colloids for silver halidephotographic light-sensitive materials which contain or are to containanionic polymers for the purposes of viscosity-increase.

This and other objects of the present invention will become apparentfrom the detailed description given hereafter.

The above object and other objects of the invention are attained by theprocess of this invention which comprises incorporating into a solutionof a binder employed in silver halide photographic light-sensitivematerials, whose viscosity has been or is to be increased with anionicpolymers, at least one compound having the formula (I): ##STR3## whereinR₁ is a hydrogen atom or an alkyl group; R₂, R₃ and R₄, which may be thesame or different, each represents a hydrogen atom, a halogen atom, analkyl group or an alkoxy group.

DETAILED DESCRIPTION OF THE INVENTION

In the general formula (I) above, R₁ represents a hydrogen atom or astraight or branched chain alkyl group having 1 to 20 carbon atoms (forexample, a methyl group, an ethyl group, an n-propyl group, an n-butylgroup, a tert-butyl group, a tert-octyl group, an n-dodecyl group, ann-heptadecyl group, an n-octadecyl group, etc.), which may also besubstituted with one or more of a sulfo group, a carboxyl group or ahalogen atom (e.g., a chlorine atom, a bromine atom, a fluorine atom,etc.).

R₂, R₃ and R₄ each represents a hydrogen atom, a halogen atom (e.g., achlorine atom, a bromine atom, etc.), a straight or branched chain alkylgroup having 1 to 6 carbon atoms and which may be substituted (e.g., amethyl group, an ethyl group, an iso-propyl group, an n-propyl group, ann-butyl group, a sec-butyl group, a tert-butyl group, a tert-amyl group,an n-hexyl group, etc.) or an alkoxy group having 1 to 6 carbon atoms(e.g., a methoxy group, an ethoxy group, an n-propoxy group, aniso-propoxy group, an n-butoxy group, an iso-butoxy group, ann-pentyloxy group, an iso-pentyloxy group, etc.).

Specific examples of compounds represented by the formula (I) above areshown below but the present invention is not to be construed as beinglimited thereto. ##STR4##

Of the above described compounds, compounds (1) and (2) are particularlypreferred due to the high degree of preservation effects achievedtherewith.

The preservation effects achieved with the compound represented by theformula (I) above are not limited to bacteria only but markedpreservation effects as to a variety of bacteria, yeasts and molds areachieved. In addition, the preservation effect is extremely high so thata sufficient amount added to hydrophilic colloids is 1/10 or less, ascompared to phenols, and the same preservation effects to the samedegree are achieved. In addition, where polymers containing acid groupsare present in the hydrophilic colloids, the compound represented by theformula (I) exhibits sufficient preservation effects and does not causeany reduction in viscosity to occur. Furthermore, the compoundrepresented by the formula (I) possesses marked preservation effectsover a wide range of pH's.

The compounds which fall within the formula (I) above are described in,for example, U.S. Pat. No. 2,870,015, in which they are employed asstabilizers or antifogging agents for photography. However, there is nodisclosure in the art that these compounds could be used aspreservatives for hydrophilic colloids for silver halide photographiclight-sensitive materials.

Of the compounds represented by the formula (I) above, the compound inwhich R₁, R₂, R₃ and R₄ each represent a hydrogen atom is described as apreservative in Farbe und Lack, Vol. 82, pages 108-125 (1976). However,there is no disclosure that such a compound would be effective as apreservative for hydrophilic colloids for silver halide photographiclight-sensitive materials. As stated above, as preservatives forhydrophilic colloids for silver halide photographic light-sensitivematerials, there must be no interaction with other photographicadditives (e.g., viscosity-increasing agents), there must be no adverseinfluences on the photographic properties, effective preservationeffects must be achieved when a small amount is used, there must be nohazards to humans, etc. It has been found that the compound representedby the formula (I) above satisfies all of these requirements.

One embodiment of the present invention comprises incorporating at leastone compound of the formula (I) above into a solution containinghydrophilic colloids, whose viscosity has been or is to be increasedwith anionic polymers containing acid groups, at any stage duringpreparation of the photographic materials. The compound of the formula(I) can be added during steps prior to coating such as duringpreparation of the silver halide photographic emulsion, whileemulsion-dispersing a coupler, during preparation of a photographiccoating solution or following the coating step. In addition, after thecompound of the formula (I) above is added, the viscosity can also beincreased using anionic polymers containing acid groups. The compoundrepresented by the formula (I) above can be added to solutionscontaining hydrophilic colloids after the compound is dissolved in wateror a water-miscible organic solvent having a boiling point lower than175° C. (for example, methanol, ethanol, acetone, dimethylformamide,ethyl acetate, etc.).

The compound represented by the formula (I) of the present invention andviscosity-increasing agents can be incorporated into various layersduring preparation of the photographic materials such as any layer ofthe photographic materials containing a hydrophilic colloid, e.g., alight-sensitive silver halide emulsion layer, a subbing layer, anintermediate layer, a filter layer, an antihalation layer, a protectivelayer, etc.

Hydrophilic colloids with which the compound represented by the formula(I) of the present invention is useful can be any kind of hydrophiliccolloid as described above or can be a combination of two or morehydrophilic colloids.

The compound represented by the formula (I) above used in the presentinvention can be employed in an amount of about 1×10⁻³ to about 5 wt%based on the dry weight of the hydrophilic colloid, preferably 1×10⁻² to2.5×10⁻¹ wt%.

The compound represented by the formula (I) above used in the presentinvention can also be incorporated into solutions containing hydrophiliccolloids as solutions after dissolving the compound in water or organicsolvents, for example, alcohols (e.g., methanol, ethanol, isopropanol,butanol, etc.), ethers (e.g., dimethyl ether, ethyl methyl ether,diethyl ether, 1-ethoxypropane, etc.), glycols (e.g., 1,2-ethanediol,1,2-propanediol, 1,3-propanediol, etc.), ketones (e.g., acetone, methylethyl ketone, 3-pentanone, etc.), esters (e.g., ethyl formate, methylacetate, ethyl acetate, etc.), amides (e.g., formamide, acetamide,succinic amide, etc.), and, of these, preferably in solvents which donot adversely affect photographic properties. Alternatively, thecompound represented by the formula (I) can also be incorporated intosolutions containing hydrophilic colloids after the compoundsrepresented by the formula (I) are dissolved in high boiling pointorganic solvents having a boiling point higher than about 180° C., e.g.,alkyl esters of phthalic acid such as methyl phthalate, ethyl phthalate,propyl phthalate, n-butyl phthalate, di-n-butyl phthalate, n-amylphthalate, isoamyl phthalate and dioctyl phthalate, etc.; alkyl amidessuch as N,N-diethyllaurylamide; trimellitic acid esters such astri-tert-octyl mellitate; phosphoric acid esters such as polyphenylphosphate, tricresyl phosphate, dioctylbutyl phosphate; citric acidesters such as acetyl tributyl citrate; etc., low boiling point organicsolvents having a boiling point of about 30° to about 150° C., such aslower alkyl acetates such as ethyl acetate, butyl acetate; ethylpropionate; sec-butyl alcohol, methyl isobutyl ketone; β-ethoxyethylacetate; methyl Cellosolve acetate; etc., or solvent mixtures thereoffollowed by emulsion-dispersion in the presence of a surface activeagent.

The viscosity-increasing agents which are preferably employed in thepresent invention include high molecular weight compounds having atleast one sulfonic acid group, carboxylic acid group or phosphoric acidgroup in the side chain thereof the represent polymers or copolymers ofmonomers containing groups such as: ##STR5## (in which M is a hydrogenatom or a cation (e.g., Na, K, NH₄, etc.)), etc., e.g., styrene sulfonicacid, 2-acrylamido-2-methylpropane sulfonic acid, acrylic acid,methacrylic acid, maleic acid, half esters of maleic acid, phosphoricacid mono esters of hydroxyethyl acrylate, a cellulose sulfuric acidsalt such as cellulose sulfate, etc. Of these high molecular weightcompounds, polystyrene sodium sulfonate, sodium polyacrylate and sodiumcellulose sulfate are particularly preferably employed.

In general, a suitable molecular weight of such a high molecular weightcompound ranges from about 50,000 to about 1,000,000, and a particularlypreferred range is 100,000 to 500,000.

The viscosity-increasing agents which are preferably used in the presentinvention are employed in an amount of from 1 to 100 wt% based on thedry weight of the hydrophilic colloid, and a particularly preferredrange is between 0.5 and 20 wt%.

The viscosity-increasing agents for coating solutions containinghydrophilic colloids can be incorporated at any stage prior to coatingduring preparation of silver halide photographic light-sensitivematerials, e.g., during preparation of the silver halide photographicemulsion, during emulsion-dispersion, during preparation of photographiccoating solutions, etc.

The silver halide emulsion which can be employed in the presentinvention is a suspension of silver halides such as silver chloride,silver bromide, silver iodide, silver chlorobromide, silver iodobromide,silver chloroiodobromide or mixtures thereof in the hydrophilic colloidsdescribed above and can be prepared in accordance with conventionalmethods. For example, the silver halide emulsion can be prepared using avariety of methods, e.g., an ammonia method, a neutral method, an acidicmethod, etc., and also a double jet method, a control jet method, etc.In addition, the silver halide emulsion can also be prepared by mixingtwo or more silver halide emulsions which are separately prepared.Processes for preparing silver halide emulsions which can be used aredescribed in, for example, C. E. K. Mees & T. H. James, The Theory ofthe Photographic Process, 3rd Ed., Macmillan Co., New York (1967), P.Grafkides, Photographic Chemistry, Fountain Press Co., Ltd., London(1958), etc.

The light-sensitive silver halide emulsion which can be employed in thepresent invention can also be chemically sensitized using the naturalsensitizers present in gelatin or in accordance with the methods asdescribed in U.S. Pat. Nos. 1,574,944, 1,623,499 and 2,410,689. Thelight-sensitive silver halide emulsion which is employed in the presentinvention can also be sensitized using palladium salts or noble metalsalts such as gold salts as described in U.S. Pat. Nos. 2,448,060,2,399,083 and 2,642,361. The light-sensitive silver halide emulsion inaccordance with the present invention can also be spectrally sensitizedusing cyanine or merocyanine dyes.

Spectral sensitization or color sensitization can be achieved usingthese cyanine dyes alone or in combination with styryl dyes or the like.The choice can be made depending upon the purpose and utility of thelight-sensitive materials such as wavelength range to be sensitized,sensitivity desired, etc.

The light-sensitive silver halide emulsion which can be employed in thepresent invention can also be reduction-sensitized with reducing agentssuch as tin (I) salts as described in U.S. Pat. No. 2,487,850,polyamines as described in U.S. Pat. Nos. 2,518,698 and 2,521,925.

The light-sensitive silver halide emulsion which can be employed in thepresent invention can also be stabilized using antifogging agents orstabilizers. Suitable compounds for these purposes are azaindenes,mercaptotetrazoles, salts of noble metals such as palladium or platinum,oximes, imidazolium salts, tetrazolium salts, etc. These compounds aredescribed in, for example, U.S. Pat. Nos. 2,444,605, 2,886,437,2,403,927, 3,266,897, 3,399,987, 2,597,915, 3,566,265 and 2,694,716.

The hydrophilic colloids which are employed in the light-sensitivematerials of the present invention can also be hardened with hardeningagents such as an aldehyde hardening agent, a methylol hardening agent,an isoxazole hardening agent, a carbodiimide hardening agent, an activehalogen hardening agent, an active vinyl hardening agent, etc. Thelight-sensitive material of the present invention may contain, as filterdyes or irradiation-preventing agents, the compounds as described inU.S. Pat. Nos. 2,274,782, 2,527,583, 2,956,879, 3,177,078 and 3,252,921,and Japanese Pat. No. 22069/1964. These dyes can also be mordanted in aparticular layer, if desired, in accordance with the method as describedin U.S. Pat. No. 3,282,699.

The light-sensitive material of the present invention may contain,individually or in combination, thiazolium salts as described in U.S.Pat. Nos. 2,131,038 and 2,694,716, azaindenes as described in U.S. Pat.Nos. 2,886,437 and 2,444,605, urazoles as described in U.S. Pat. No.3,287,135, sulfocatechols as described in U.S. Pat. No. 3,236,652,mercaptotetrazoles as described in U.S. Pat. Nos. 2,403,927, 3,266,897and 3,397,987, nitrones and indoles as described in British Pat. No.2,728,663.

The light-sensitive material of the present invention can containfluorescent brightening agents such as stilbenes, triazines, oxazoles,coumarins; water-soluble whitening agents as described in German Pat.No. 972,067 and U.S. Pat. No. 2,933,390; oil-soluble whitening agents asdescribed in German Patent 1,150,274 and U.S. Pat. No. 3,406,070.

The light-sensitive material of the present invention can also containUV absorbants, e.g., benzotriazoles as described in U.S. Pat. No.3,253,921, thiazolidines as described in U.S. Pat. No. 2,739,888,thiazolidones as described in U.S. Pat. No. 2,739,971.

The light-sensitive material of the present invention can furthercontain, as color fog preventing agents, the hydroquinone derivatives asdescribed in U.S. Pat. Nos. 2,360,290, 2,336,327, 2,384,658, 2,403,721,2,418,613, 2,675,314, 2,701,197, 2,704,713, 2,728,659, 2,732,300 and2,735,765.

All of the open chain type ketomethylene yellow dye forming couplers canbe advantageously employed in the lightsensitive material of the presentinvention. Typical examples of such couplers include benzoylacetanilidetype and pivalylacetanilide type couplers. In addition, all magentacolor forming couplers such as pyrazolone type and indazolone typecouplers, etc., can be advantageously used. Further, all cyan colorforming couplers such as phenol type, naphthol type, etc., couplers canbe advantageously employed. These color couplers can possess acoupling-off group on the active carbon atom at the coupling position.Diffusion resistant couplers having a ballast group in the molecule ofthe color couplers are preferred. The terms "coupling-off group","ballast group" and "diffusion resistant" are used herein in theirconventional meaning with respect to color couplers and are wellunderstood by one skilled in the art.

Hydrophobic groups having at least 8 carbon atoms such as an alkyl groupor an alkylaryl group as a ballast group can be introduced into thecoupler molecules using conventional methods to render the couplersdiffusion resistant. The ballast group can be connected directly to thecoupler skeleton, or through an amino bond, an ether bond, a thioetherbond, a carbamido bond, a sulfamido bond, a urea bond, an ester bond, animido bond, a carbonyl bond, a sulfonyl bond, etc., thereto.

Representative diffusion resistant couplers which can be used in thepresent invention are described below in detail.

Open chain diketomethylene type compounds are widely employed in generalas yellow color dye forming couplers. Specific examples thereof aredescribed in, for example, U.S. Pat. Nos. 3,341,331, 2,875,057 and3,551,155, German patent application (OLS) No. 1,547,868, U.S. Pat. Nos.3,265,506, 3,582,322, and 3,725,072, German patent application (OLS) No.2,162,899, U.S. Pat. Nos. 3,369,895 and 3,408,194, German patentapplication (OLS) Nos. 2,057,941, 2,213,461, 2,219,917, 2,261,361 and2,263,875.

5-Pyrazolone type compounds are mainly employed as magenta color formingcouplers, but indazolone type compounds and cyanoacetyl compounds arealso employed. Examples thereof are described in, for example, U.S. Pat.Nos. 2,439,098, 2,600,788, 3,062,653 and 3,558,319, British Pat. No.956,261, U.S. Pat. Nos. 3,582,322, 3,615,506, 3,519,429, 3,311,476 and3,419,319, Japanese patent application Nos. 21454/1973 and 56050/1973,German patent application (DT-AS) 1,810,464, Japanese Patent No.2016/1969, Japanese patent application (OPI) No. 131448/1974, U.S. Pat.No. 2,983,608, etc.

Phenol or naphthol derivatives are mainly employed as cyan color formingcouplers. Specific examples thereof are described in, for example, U.S.Pat. Nos. 2,369,929, 2,474,293, 2,698,794, 2,895,826, 3,311,476,3,458,315, 3,560,212, 3,582,322, 3,591,383, 3,386,301, 2,434,272,2,706,684, 3,034,892, and 3,583,971, German patent application (OLS) No.2,163,811, Japanese Pat. No. 28836/1970, Japanese patent application(OPI) No. 122335/1974, etc.

In addition, development inhibitor-releasing type couplers (theso-called "DIR" couplers) or compounds releasing development inhibitorscan also be present during the color forming reaction. Specific examplesthereof are described in U.S. Pat. Nos. 3,148,062, 3,227,554, 3,253,924,3,617,291, 3,622,328 and 3,705,201, British Pat. No. 1,201,110, U.S.Pat. Nos. 3,297,445, 3,379,529 and 3,639,417, Japanese patentapplication (OPI) Nos. 122335/1974 and 129536/1974, etc.

Two or more of the couplers described above and like couplers can bepresent in the same layer or the same coupler can also be present in twoor more layers in order to satisfy properties required for thelight-sensitive material.

The couplers and other photographic addenda can be introduced intohydrophilic colloids in photographic materials using known methods. Themethods described in, for example, U.S. Pat. No. 2,322,027, etc., can beused. In general, after dissolving the couplers, etc., in high boilingpoint organic solvents having a boiling point higher than about 180° C.,e.g., alkyl esters of phthalic acid such as methyl phthalate, ethylphthalate, propyl phthalate, n-butyl phthalate, di-n-butyl phthalate,n-amyl phthalate, isoamyl phthalate and dioctyl phthalate, etc.; alkylamides such as N,N-diethyllaurylamide; trimellitic acid esters such astri-tert-octyl mellitate; phosphoric acid esters such as polyphenylphosphate, tricresyl phosphate, dioctylbutyl phosphate; citric acidesters such as acetyl tributyl citrate; or low boiling point organicsolvents having a boiling point of about 30° to about 150° C., such aslower alkyl acetates such as ethyl acetate, butyl acetate; ethylpropionate; sec-butyl alcohol, methyl isobutyl ketone; β-ethoxyethylacetate; methyl Cellosolve acetate; etc., the solution thereof isdispersed in known hydrophilic colloids for photography. These highboiling point organic solvents and low boiling point organic solventscan be used in combination, if desired.

In addition, where the couplers possess acid groups such as carboxylicacid or sulfonic acid groups, the couplers can be introduced intohydrophilic colloids as an alkaline aqueous solution thereof.

The light-sensitive material in accordance with the present inventioncan also contain surface active agents, for example, natural surfaceactive agents such as saponin, nonionic surface active agents such asalkyleneoxide type, glycerin type, glycidol type, etc., surface activeagents; cationic surface active agents such as higher alkyl amines,quaternary ammonium salts, pyridine and other heterocyclic ringcompounds, phosphoniums or sulfoniums, etc.; anionic surface activeagents containing acid groups such as carboxylic acid groups, sulfonicacid groups, sulfuric acid groups, sulfate groups, phosphate, groups,etc.; amphoteric surface active agents such as amino acids,aminosulfonic acids, sulfates or phosphates of aminoalcohols, etc.

The light-sensitive material in accordance with the present inventioncan further contain color developers, development inhibitor releasing(DIR) compounds, diffusible dye releasing (DDR) couplers, etc.

The photographic coating solution used in the present invention iscoated onto substantially planar materials which do not undergo a markedchange in dimensional stability during processing, for example,depending upon purpose, a rigid support such as glass, a metal or aceramic, or a flexible support. Representative examples of flexiblesupports are those conventionally employed in photographiclight-sensitive materials and examples include a cellulose nitrate film,a cellulose acetate film, a cellulose acetate butyrate film, a celluloseacetate propionate film, a polystyrene film, a polyethyleneterephthalate film, a polycarbonate film, or a laminate thereof, a thinglass plate, paper, and the like. Baryta paper on which an α-olefinpolymer, particularly an α-olefin polymer having 2 to 10 carbon atomssuch as polyethylene, polypropylene, ethylene butene copolymers arecoated or laminated and synthetic resin films, to which adhesion withother high molecular weight substances has been improved and on whichprintability has been improved, by roughening the surface thereof, canalso be used advantageously.

These supports can be transparent or opaque supports depending upon thepurpose of the light-sensitive materials. In addition, in the case oftransparent supports, not only colorless transparent supports but alsocolored transparent supports obtained by adding dyes and pigmentsthereto can be employed. Colored transparent supports are well known andare used in the field of X-ray films, etc., as reported in J. SMPTE 67,296 (1958), etc.

Suitable opaque supports include, in addition to supports which areintrinsically opaque such as paper, those obtained by adding dyes orpigments such as titanium oxide, etc., to transparent films, syntheticresin films surface treated using the method as described in JapanesePat. No. 19068/1972, paper or synthetic resin rendered completely lightshielded by adding carbon black, dyes, etc., thereto. When adhesionbetween the support and the photographic emulsion layers isinsufficient, a layer adhesive to both layers is usually provided as asubbing layer. In addition, in order to further improve adhesion, thesurface of the support can also be preliminarily treated using a coronadischarge treatment, a UV light irradiation, a flame treatment, etc.

Each of the layers of the photographic lightsensitive materials can beformed by coating using a variety of coating methods including dipcoating, air knife coating, curtain coating, or extrusion coating usinga hopper as described in U.S. Pat. No. 2,681,294.

Two or more layers can be coated simultaneously using the methods asdescribed in U.S. Pat. Nos. 2,761,791, 3,508,947, 2,941,898 and3,526,528, etc., if desired.

Any conventional methods can be employed for processing the photographiclight-sensitive material prepared in accordance with the presentinvention. The processing temperature generally ranges between about 18°and about 50° C., but the temperature can be lower than about 18° C. orhigher than about 50° C. Depending upon purpose, development processingfor forming silver images (black-and-white photographic processing) andcolor photographic processing comprising development processing forforming color images can be employed.

Suitable developing agents for developers which can be employed forblack-and-white photographic processing can be known developing agentssuch as dihydroxybenzenes (e.g., hydroquinone), 3-pyrazolidones (e.g.,1-phenyl-3-pyrazolidone), aminophenols (e.g., N-methyl-p-aminophenol),1-phenyl-3-pyrazolines, and ascorbic acid. The developers can contain,in addition, known preservatives, alkali agents, pH buffering agents,antifogging agents, and the like, and, further, as necessary,dissolution aids, color toning agents, development accelerators, surfaceactive agents, defoaming agents, hard water softening agents, hardeningagents, viscosity-imparting agents, etc.

Suitable color developing agents which can be advantageously employedinclude all known conventional aromatic amine dye forming developingagents, for example, N,N-diethyl-p-phenylenediamine,N-ethyl-N-hydroxyethyl-p-phenylenediamine,N-ethyl-N-hydroxyethyl-2-methyl-p-phenylenediamine,N-ethyl-β-N-methanesulfonamidoethyl-3-methyl-4-aminoaniline,N,N-dimethyl-2-methyl-p-phenylenediamine and the sulfates,hydrochlorides, sulfites, etc., thereof. In addition, the colordevelopers can contain conventionally employed additives, for example,sulfites, carbonates, bisulfites, bromides and iodides of alkali metals,benzyl alcohol, etc.

Conventional processing baths such as a bleaching bath, a fixing bath, astabilizing bath, etc., can be advantageously employed. Baths capable ofaccomplishing a combination of these functions can also be employed.

As described above, the preservatives used for photography should meetall of the photographic requirements set forth above, in addition to themain preserving activity achieved. In particular, it is particularlyimportant for these preservatives to not adversely affect sensitivity,gamma and fog. The compound represented by the formula (I) does notadversely influence these photographic properties. This lack of adversephotographic influence is demonstrated by the Reference Example below,wherein sulfur sensitized and gold sensitized silver halide emulsionswere employed since gold and sulfur sensitized emulsions are moresensitive to any change in sensitivity, gamma and fog, than anon-sensitized silver halide emulsion.

REFERENCE EXAMPLE

A 3.0 wt% methanol solution of Compound (1) was added to 100 g of asilver chlorobromide emulsion (containing 0.06 mol of silver and 10 g ofgelatin) containing 30 mol% of silver bromide which had been sulfursensitized and gold sensitized, immediately before completion of postripening of the emulsion, at 50° C. The emulsion was coated onto acellulose triacetate transparent support (silver coated amount: 2.0g/m²).

This sample was exposed to light for 1/50 second through a silver wedgeusing a tungsten light source having a color temperature of 2854° K.,and then developed with a Kodak D-16 Developer, at 20° C. for 6 minutes.Thereafter, fixing, washing with water and drying were conducted in aconventional manner. The density was then measured with an automaticdensitometer made by the Fuji Photo Film Co., Ltd. The photographicproperties obtained are shown in Table A below.

                  TABLE A                                                         ______________________________________                                               Amount of Compound                                                            (I) Added                                                              Sample (wt %/gelatin) Sensitivity                                                                             Gamma  Fog                                    ______________________________________                                        XX     --             1.14      2.95   0.10                                   XXI    0.1            1.15      2.92   0.10                                   XXII   1              1.14      2.96   0.10                                   ______________________________________                                    

As can be easily seen from the results in Table A, the photographicproperties hardly change even if the compound as used in the presentinvention is employed.

The present invention is now explained in more detail by reference tothe following Examples of the present invention. Unless otherwiseindicated, all parts, percents, ratios and the like are by weight.

EXAMPLE 1

A sample prepared by adding 80 ml of a 2% aqueous solution of sodiumpolystyrene sulfonate (molecular weight: about 100,000) to 920 ml of agelatin aqueous solution containing 100 g of gelatin and then addingphenol thereto in an amount of 1.25 wt% based on the dry gelatin (Sample(I)), a sample obtained by adding Compound (1) of the present inventionin an amount of 0.1 wt% based on the dry gelatin (Sample (II)), andsamples corresponding to Samples (I) and (II) but obtained by addingsodium cellulose sulfate instead of the polystyrene sodium sulfonate(Samples (III) and (IV)) were prepared. As degradation proceeded,decomposition of gelatin proceeded so that the viscosity decreased.Thus, the viscosity was taken as a measure of the degree of degradation.The solutions were sealed and stored at 40° C. The viscosity (incentipoise) thereof was measured with a B-type rotary viscometer(temperature: 40° C.; Rotor No.: No. 1; RPM: up to 100 cps, 60 rpm;100-200 cps, 30 rpm; 200-500 cps, 12 rpm) and the results obtained areshown in Table 1 below.

                  TABLE 1                                                         ______________________________________                                                 Sample                                                                        I       II        III      IV                                        ______________________________________                                        Viscosity- Sodium    Sodium    Sodium Sodium                                  Increasing Polystyrene                                                                             Polystyrene                                                                             Cellulose                                                                            Cellulose                               Agent      Sulfonate Sulfonate Sulfate                                                                              Sulfate                                 Preservative                                                                             Phenol    Com-      Phenol Com-                                                         pound (1)        pound (1)                               Viscosity                                                                      Fresh     110       115       178    180                                      3 Days after                                                                             60       110        70    180                                     ______________________________________                                    

As can be seen from he results in Table 1 above, when Compound (1) wasused as in the present invention, as a preservative, the viscosity wasreduced less and the preservation effects were excellent, while theamount was about 1/12 times that of phenol.

EXAMPLE 2

The preservatives as used in the present invention and phenol were addedto an aqueous gelatin solution, containing 1.5 wt% of sodium polystyrenesulfonate or sodium cellulose sulfate as viscosity-increasing agentsbased on the dry gelatin, in amounts of 1 wt% and 5 wt%, respectively,based on the dry gelatin. Thus, the final gelatin concentration was7.5%. The viscosities of these solutions were measured using the samemethod as in Example 1 and the results obtained are shown in Table 2below.

                                      TABLE 2                                     __________________________________________________________________________    Sample No.                                                                    Viscosity-              Sodium Polystyrene Sulfate                                                                      Sodium Cellulose Sulfate            Increasing                                                                          None              (1.5 wt %/gelatin)                                                                              (1.5 wt %/gelatin)                  Agent V   VI VII                                                                              VIII                                                                              IX  X   XI XII                                                                              XIII                                                                              XIV XV  XVI                                                                              XVII  XVIII                                                                             XIX                __________________________________________________________________________    Preserva-                                                                           None                                                                              Phe-                                                                             Phe-                                                                             Com-                                                                              Com-                                                                              None                                                                              Phe-                                                                             Phe-                                                                             Com-                                                                              Com-                                                                              None                                                                              Phe-                                                                             Phe-  Com-                                                                              Com-               tive      nol                                                                              nol                                                                              pound                                                                             pound   nol                                                                              nol                                                                              pound                                                                             pound   nol                                                                              nol   pound                                                                             pound                              (1) (1)           (1) (1)              (1) (1)                Preserva-                                                                     tive                                                                          Amount                                                                              --  1  5  1   5   --  1  5  1   5   --  1  5     1   5                  Added                                                                         (wt %/                                                                        gelatin)                                                                      Viscosity                                                                           16  16 15 16  16  150 115                                                                              50 150 150 230 170                                                                              40    230 150                __________________________________________________________________________

From the results shown in Table 2, the following conclusions can bedrawn. Where phenol is added to the gelatin solution (Sample XII andSample XVII) in an amount sufficient to achieve sufficient preservationeffects, the viscosity becomes extremely low as a result of theinhibition of the viscosity-increasing effect by phenol. On the otherhand, Compound (1) of the present invention causes an extremely smallreduction in viscosity to occur even when a large amount thereof is usedbased on the dry gelatin. Thus, the viscosity-increasing effect of theviscosity-increasing agent is not inhibited by the preservative.

COMPARISON EXAMPLE

In order to examine the preservation effects, a sample was prepared byadding 0.1 wt% of Compound (1) as used in the present invention based onthe dry gelatin (Sample (XX)), samples obtained by adding 0.1, 1.25 and2.5 wt% of phenol respectively, based on the dry gelatin (Sample (XXII),Sample (XXIII), and Sample (XXIV)) and a sample obtained by adding 0.1wt% of neomycin (as described in Japanese Pat. No. 14081/1967) based onthe dry gelatin (Sample (XXI)) to a 10 wt% aqueous gelatin solution. Theviscosity and turbidity were measured immediately after preparation ofthese solutions, after storage for 3 days at 40° C., and after storagefor 6 days at 40° C. The results obtained are shown in Table 3 below.Turbidity was determined by measuring the absorbance at 550 nm.

                  TABLE 3                                                         ______________________________________                                               Sample                                                                        XX      XXI       XXII    XXIII XXIV                                   ______________________________________                                        Preservative                                                                           Compound                                                             Amount   (1)       Neomycin  Phenol                                                                              Phenol                                                                              Phenol                               Added    0.1       0.1       0.1   1.25  2.5                                  (%/dry                                                                        gelatin                                                                       Fresh                                                                         Viscosity                                                                     (cps)    22        21        21    22    22                                   Turbidity                                                                              21        21        21    22    21                                   3 Days                                                                        Storage                                                                       Viscosity                                                                     (cps)    19        19        6     18    19                                   Turbidity                                                                              23        25        52    35    23                                   6 Days                                                                        Storage                                                                       Viscosity                                                                     (cps)    17        15        3.5   5.6   15                                   Turbidity                                                                              23        26        73    55    23                                   ______________________________________                                    

As is clear from the results in Table 3, Compound (1) of the presentinvention exhibits excellent preservation effect.

While the invention has been described in detail and with reference tospecific embodiments thereof, it will be apparent to one skilled in theart that various changes and modifications can be made therein withoutdeparting from the spirit and scope thereof.

What is claimed is:
 1. A method for preventing the degradation of ahydrophilic colloid solution by the action of bacteria, mold or yeastfor a silver halide photographic light-sensitive material, in which theviscosity of the solution thereof has been or is to be increased usingan anionic polymer containing an acid group, whereafter said hydrophiliccolloid solution is used in a multi-coating process at a speed of about20 m/min or more, which comprises incorporating into said hydrophiliccolloid solution at least one compound represented by the formula (I):##STR6## wherein R₁ represents a hydrogen atom or an alkyl group; andR₂, R₃ and R₄, which may be the same or different, each represents ahydrogen atom, a halogen atom, an alkyl group or an alkoxy group and,increasing said viscosity if said viscosity has not already beenincreased by the addition of said anionic polymer by adding said anionicpolymer containing an acid group to said hydrophilic colloid soluton,whereby said degradation is prevented without any adverse effect onviscosity increase.
 2. The method of claim 1, wherein said hydrophiliccolloid is gelatin or a gelatin derivative.
 3. The method of claim 1,wherein R₁ through R₄ are all hydrogen atoms.
 4. The method of claim 1,wherein said anionic polymer is a polymer having a sulfonyl group, acarboxyl group or a sulfato group.
 5. The method of claim 1, whereinsaid compound is incorporated in an amount of about 1×10⁻² to about2.5×10⁻¹ wt% based on the dry weight of the hydrophilic colloid.
 6. Themethod of claim 4, wherein said anionic polymer is at least one polymerselected from a polystyrene sulfonic acid salt and a cellulose sulfuricacid salt.
 7. The method of claim 1, wherein the viscosity has alreadybeen increased.
 8. The method of claim 1, wherein the viscosity has notbeen increased and is increased by adding said anionic polymer.
 9. Themethod of claim 1, wherein the acid group is at least one sulfonic acidgroup, carboxylic acid group or sulfonic acid group, and the acid groupis present in a side chain of the anionic polymer.
 10. The method ofclaim 9, wherein the anionic polymer containing an acid group isselected from polymers or copolymers of monomers from the classconsisting of styrene sulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, acrylic acid, methacrylic acid, maleic acid, half estersof maleic acid, phosphoric acid mono esters of hydroxyethyl acrylate anda cellulose sulfuric acid salt.
 11. The method of claim 9, wherein theanionic polymer containing an acid group is selected from the classconsisting of polystyrene sodium sulfonate, sodium polyacrylate andsodium cellulose sulfate.
 12. The method of claim 10, wherein theanionic polymer having an acid group is present in an amount of 1 to 100wt % based on the dry weight of the hydrophilic colloid.
 13. The methodof claim 11, wherein the anionic polymer having an acid group is presentin an amount of 1 to 100 wt % based on the dry weight of the hydrophiliccolloid.
 14. The method of claim 1, wherein the compound of generalformula (I) and the anionic polymer having an acid group are present ina non-light sensitive hydrophilic colloid solution.